Association between CYP1A1 rs4646903 T > C genetic variations and male infertility risk: A meta-analysis

BACKGROUND: Number of studies have been performed to investigate the relationship between the CYP1A1 rs4646903 polymorphism and male infertility risk, but the sample size was small and the results were conflicting. A meta-analysis was performed to assess these associations. METHODS: A systematic search was conducted to identify all relevant studies from Medline, Web of science, Embase, China biology medical literature database (CBM), China National Knowledge Infrastructure (CNKI), WanFang and Weipu (VIP) databases up to June 30, 2018. The odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of associations. All of the statistical analyses were conducted using Revman 5.3 and Stata 14.0. RESULTS: Ten studies involved 3028 cases and 3258 controls. Overall, significant association was observed between the CYP1A1 rs4646903 polymorphism and male infertility (C vs T: OR = 1.42, 95%CI = 1.14-1.76; CC vs TT: OR = 2.13, 95%CI = 1.36-3.34; CC vs CT+TT: OR = 1.96, 95%CI = 1.30-2.95; CC+CT vs TT: OR = 1.51, 95%CI = 1.16-1.97). In subgroup analysis by ethnic group, a statistically significant association was observed in Asians (C vs T: OR = 1.59, 95%CI = 1.22-2.08), but not in Non-Asians (C vs T: OR = 1.01, 95%CI = 0.79-1.30). Additionally, none of the individual studies significantly affected the association between CYP1A1 rs4646903 polymorphism and male infertility, according to sensitivity analysis. CONCLUSION: Our meta-analysis supports that the CYP1A1 rs4646903 polymorphism might contribute to individual susceptibility to male infertility in Asians.